With developments in technologies, electronic games based on devices such as computers, tablet computers and cell phones become more and more popular and convenient. In addition, game consoles extend the popularity of games as well, and provide more interesting game functions by introducing contents of motion sensing and computer vision into game devices.
A virtual game is often controlled by controls input by a user. For example, the user can operate a game controller, or the game can identify user gestures and motions, by which more vivid and involving games can be made.